It took just 3 minutes and 48 seconds for Taylor Swift to convince me that she’s the real deal. That would be the elapsed time of her third album’s first and best track, “Mine.”

With it, the talented and enormously successful 20-year-old singer-songwriter has invented a new genre: country power-pop. “Mine” brings together the polish of modern country with the explosiveness of guitar-driven pop-rock at its most dynamic. Add an irresistible melody and compelling lyrics and you have the total package.

On her first two best sellers, Swift seemed at times to vacillate between country, pop and confessional-songwriter folk, as if unsure in which realm she belonged.

With “Speak Now,” she sounds much more focused and assured, regardless of what type of music she’s performing.

Its first seven songs are as solid an opening salvo as you’re likely to hear from a mainstream artist this year. “Sparks Fly” and “The Story of Us” are two more first-rate guitar-powered rockers, “Back to December” is a regretful big ballad and the nimbly rendered interrupted-wedding saga of the title track is simply a hoot and a half.

The second half bogs down some with the appearance of more orchestrated and overlong tracks such as “Enchanted” and “Haunted,” during which Swift steps off the accelerator and indulges in her penchant for melodrama. But even at her most labored, she still shows great skill at crafting hooky choruses, melodic bridges and appealing vocal arrangements; it just takes a little longer for them to unfold.

Two excellent ballads are tucked into the second half as well: the surprisingly prescient lullaby “Never Grow Up” and the defiant, us-against-the-world anthem “Long Live.”

The extended version of “Speak Now,” available at Target, contains three songs not on the standard album, three variations of songs that are on the regular version, and a video of “Mine.” It’s worth getting for the three non-album songs alone. All are of high-enough quality to have been included on “Speak Now,” especially the sparkling “Superman.”

Sam Gnerre has worked for the Daily Breeze in Torrance since 1984. He grew up in Fontana, Calif., and is a graduate of Fontana High School. He earned a B.A. in English literature from the University of California, Riverside, and a Master's degree in library science from UCLA. He was hired at the Daily Breeze in 1984 to help with the conversion of the paper's manual clip file system to an online database of archived stories. Currently, he writes the paper's weekly News Quiz, does a weekly music CD review, and researches and writes local history articles for the South Bay History blog, in addition to his current duties as a night website editor for the Southern California News Group.